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Drug Information
Pharmacokinetics
| Indication
& Dosage | Action
| Interacations
Adverse
Effects &Precautions |
Brands available in Market
Pyrazinamide is readily absorbed from the gastrointestinal tract. Peak serum concentrations occur about 2 hours after a dose by mouth and have been reported to be about 35 micrograms per mL after 1.5 g, and 66 micrograms per mL after 3 g. Pyrazinamide is widely distributed in body fluids and tissues and diffuses into the CSF. The half-life has been reported to be about 9 to 10 hours. It is metabolised primarily in the liver by hydrolysis to the major active metabolite pyrazinoic acid which is subsequently hydroxylated to the major excretory product 5-hydroxypyrazinoic acid. It is excreted through the kidney mainly by glomerular filtration. About 70% of a dose appears in the urine within 24 hours mainly as metabolites and 4 to 14% as unchanged drug. Pyrazinamide is removed by dialysis. Pyrazinamide is distributed into breast milk.
Indication
& Dosage
Oral
TUBERCULOSIS: As part of multi-dose regimes during the first two months.
May be continued if necessary into continuation phase also. Adults:
20-35mg/kg/day as a single dose. Dialy max 3g. Intermittent therapy:
50mg/kg thrice a week or 75mg/kg twice a week. One scheme is
Children: 15-30mg/kg as a single dose. Max 2g daily.
Action
Bactericidal action against M. tuberculosis in acid
environment present in macrophages and inflammed tissue. Together with
rifampicin provides greatest sterilising action with reduction in
relapse rate. Reduces tubular secretionof uric acid.
Uricosurics: Antagonism of effect of probencid and
sulphinpyrazone.
INH: Significantly reduces INH serum concentration.
Anti-diabetic agents: Affects control of diabetes in diabetics.
Adverse Effect & Precautions
Nausea, vomiting, myalgia, arthralgia hyperuricaemia and hepatotoxicity.
Rarely hypersensitivity reactions.
Precaution: Periodic liver function test and serum uric acid levels,
diabetes mellitus.
Pregnancy: To given only if clearly needed.
Breast Feeding: Use with caution.
Man: May be used with caution.
